Heretofore, various types of polyurethanes have been made from polyester or polyether polyols. Such thermoplastic polyurethanes are generally incompatible with polyolefins such as polypropylene.
U.S. Pat. No. 5,589,543, to Yokelson et al., relates to hydrophobic polyurethane elastomers containing a linear soft segment without pendant chain-branched groups, wherein said polyurethane elastomer has a glass transition temperature (Tg) of less than -70.degree. C., and a moisture uptake of less than 1.0 wt. % after 24 hours of immersion in water at 70.degree. C., and wherein said polyurethane elastomer comprises at least one repeat unit containing said linear soft segment, which soft segment comprises a moiety derived from a polyol which is an unsaturated hydrocarbon polyol.
PCT International Application Publication No. WO 97/00901, to Cenens, relates to a thermoplastic polyurethane formed from a polydiene diol, preferably a hydrogenated polybutadiene diol, having from 1.6 to 2 terminal hydroxyl groups per molecule and a number average molecular weight between 500 and 20,000, an isocyanate having two isocyanate groups per molecule, and optionally a chain extender having two hydroxyl groups per molecule. The thermoplastic polyurethane composition is prepared by a prepolymer method, preferably a solventless prepolymer method using a branched chain extender.
European Patent Application No. EP 0 732 349, to Kaufhold, relates to a thermoplastic polyurethane resin prepared by reacting an isocyanate, a polyol, a reactive polyolefin, and a chain extender. The resin is blended with polypropylene.